Gas detector tubes, which are filled with a reactant, which reacts with a chemical compound to be determined in an optically detectable reaction, are known from the state of the art. For example, a defined quantity of a gas mixture is pumped with a hand pump through the gas detector tube. A concentration of the chemical compound to be measured is subsequently determined by means of a discoloration of the reactant.
Moreover, so-called chip-based measuring systems are known, in which the reactant is arranged in reaction chambers on a reaction carrier, which can be inserted into a measuring device. The measuring device detects the reaction carrier and carries out a corresponding measuring method for measuring a concentration of the corresponding component of the gas mixture. For example, the reaction carrier has a plurality of reaction chambers, which may each be used for a measurement. A mechanical locking pin, which protrudes in unused reaction chambers, so that it can lock on the measuring device, is provided for each reaction chamber. The corresponding locking pin is pressed in during a measurement with a reaction chamber. Upon inserting the reaction carrier into the measuring device, the reaction carrier is always inserted into the measuring device until the first protruding locking pin mechanically locks in the measuring device and thus the first unused reaction chamber is always used for the respective measurement. After completion of the measurement, the reaction carrier is always completely ejected from the measuring device. An independent positioning of the reaction carrier in the measuring device in a desired relative position is not possible.